Prospective Evaluation of the Alterations in the Morphology and Vascular Resistance of the Renal Parenchyma with Color Doppler Ultrasonography after Percutaneous Nephrolithotomy

Abstract

To evaluate the kidneys with color Doppler ultrasonography (CDUS) to determine whether percutaneous nephrolithotomy (PNL) causes renal parenchymal damage. In 24 patients who underwent unilateral PNL with single renal pole access, cortical thickness, echogenicity, and resistive index (RI) were measured in each pole of the operated and contralateral kidney separately before and at postoperative day (POD) 1, and at 3, 6, and 12 months after PNL. The mean age of the patients was 36.67 +/- 14.68 years. The serum creatinine level increased significantly immediately after PNL but diminished to the preoperative level at POD 1. Changes in serum blood urea nitrogen and electrolyte levels were insignificant. Mean cortical thickness increased significantly in the access pole and contralateral kidney and insignificantly in the nonaffected pole. No statistically significant change was recorded in parenchymal echogenicitiy. Statistically significant differences in cortical thickness between the access pole and the contralateral kidney and between the nonaffected pole and the contralateral kidney disappeared 3 months later. Differences in mean cortical thickness between the access pole and the nonaffected pole were insignificant at all examination periods. Echogenicity was greater in the access pole and the nonaffected pole than in the contralateral kidney only at POD 1. No significant difference was noted in the echogenicity between the access pole and the nonaffected pole. Mean RIs were lower than the universally accepted pathologic RI level (0.70) at all periods. There was no statistically significant difference between the mean RI values of the access pole, nonaffected pole, and contralateral kidney. PNL does not cause obvious renal dysfunction and significant parenchymal scarring, which is indicated by the decrease in cortical thickness and increases in cortical echogenicity and intrarenal RI.